On Tuesday 10 April 2007 14:42, Josh Fisher wrote: > > Kern Sibbald wrote: > > On Monday 09 April 2007 21:22, Josh Fisher wrote: > > > >> Kern Sibbald wrote: > >> > >>> On Monday 09 April 2007 16:20, Josh Fisher wrote: > >>> > >>> > >>>> There's no reason they cannot use the same pool. They just cannot write > >>>> to the same volume concurrently. With a tape device, that would be a > >>>> problem because there can only be one volume in the tape drive. > >>>> > >>>> > >>> True. > >>> > >>> > >>> > >>>> However > >>>> with a disk device, a volume is a file, so there can be numerous volumes > >>>> being written concurrently. > >>>> > >>>> > >>> This is not true within Bacula. For each Device (tape, DVD, disk, > >>> > > FIFO, ...) > > > >>> Bacula has a single file descriptor thus only one Volume can be open for > >>> > > each > > > >>> Device, whether tape or disk. Multiple jobs can be simultanously writing > >>> > > to > > > >>> that Volume. However, since a Volume can be in only one Pool, and since > >>> > > you > > > >>> can only write to one Volume per Device, you can only be simultaneously > >>> writing to one Pool per Device. > >>> > >>> To simultaneously write to more than one Pool, you need multiple Devices. > >>> > >>> > >>> > >> Yes. I guess I didn't phrase that very carefully. I believe Kyle has two > >> pools, "local_pool" and "remote_pool", and each pool is using a > >> different Storage resource by specifying Storage= in the Pool resource > >> definition. I assume the Storage resources are pointing to two different > >> SD devices. > >> > > > > OK. > > > > > >> In that case, specifying Maximum Volume Jobs = 1 in both of > >> the pools should prevent the possibility of interleaving. > >> > > > > That's not the best way to resolve the problem, and is likely to fail because > > of subtle timing problems if you are running two jobs simultaneously. > > > > To prevent interleaving of blocks, either restrict the number of simultaneous > > jobs for that Device using any number of methods such as priorities, Max > > simultaneous jobs for the Storage,... , or use Spooling. > > > > OK. I had thought that with Max Volume Jobs = 1 there could only be one > job writing to a volume, since a device can have only one volume > mounted, and that any other jobs would have to wait on the device > because they would require a different volume.
Max Volume Jobs is not designed as a concurrency control, so is unlikely to function as such, and as I mentioned will for that reason likely have race problems. > So Maximum Concurrent > Jobs = 1 in the Storage resource will always prevent interleave?. I believe that is what I implied above. Try it and see :-) > > > > >> A volume from > >> local_pool can be written concurrently with a volume from remote_pool, > >> but only one job at a time can write to a local_pool volume and only one > >> job at a time can write to a remote_pool volume. > >> > >> > >>>> One way is to use Maximum Volume Jobs = 1 in > >>>> the Pool resource definition. This will cause a new volume (ie. file) to > >>>> be used for each job that is run. > >>>> > >>>> Kyle Tucker wrote: > >>>> > >>>> > >>>>> Hi, > >>>>> I have a new Bacula 2.0.2 setup and I am backing up to > >>>>> disk. I have remote clients that are very slow to backup and > >>>>> often prevent my more important local clients from being backed > >>>>> up due to concurrency being set to 1 as I don't want to get into > >>>>> the issues with interleaving as it's suggested to avoid in the > >>>>> warning section on concurrent jobs. > >>>>> I already have things so my remote clients are in separate > >>>>> pools and I understand I can set these pools into separate Device > >>>>> resources and Bacula will allow 2 concurrent jobs to run. Is there > >>>>> a way that I can limit the 2 concurrent jobs to not run within the > >>>>> same pool, causing the interleaving blocks issue? I looked at using > >>>>> priorities, but that didn't look like it would control what I am > >>>>> trying to do here. Thanks. > >>>>> > >>>>> > >>>>> > >>>>> > >>>> ------------------------------------------------------------------------- > >>>> Take Surveys. Earn Cash. Influence the Future of IT > >>>> Join SourceForge.net's Techsay panel and you'll get the chance to share > >>>> > > your > > > >>>> opinions on IT & business topics through brief surveys-and earn cash > >>>> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > >>>> _______________________________________________ > >>>> Bacula-users mailing list > >>>> Bacula-users@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/bacula-users > >>>> > >>>> > >>>> > >>> ------------------------------------------------------------------------- > >>> Take Surveys. Earn Cash. Influence the Future of IT > >>> Join SourceForge.net's Techsay panel and you'll get the chance to share > >>> > > your > > > >>> opinions on IT & business topics through brief surveys-and earn cash > >>> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > >>> _______________________________________________ > >>> Bacula-users mailing list > >>> Bacula-users@lists.sourceforge.net > >>> https://lists.sourceforge.net/lists/listinfo/bacula-users > >>> > >>> > >>> > >> ------------------------------------------------------------------------- > >> Take Surveys. Earn Cash. Influence the Future of IT > >> Join SourceForge.net's Techsay panel and you'll get the chance to share your > >> opinions on IT & business topics through brief surveys-and earn cash > >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > >> _______________________________________________ > >> Bacula-users mailing list > >> Bacula-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/bacula-users > >> > >> > > > > ------------------------------------------------------------------------- > > Take Surveys. Earn Cash. Influence the Future of IT > > Join SourceForge.net's Techsay panel and you'll get the chance to share your > > opinions on IT & business topics through brief surveys-and earn cash > > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > > _______________________________________________ > > Bacula-users mailing list > > Bacula-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/bacula-users > > > > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
